Generally, wind power generating systems convert kinetic energy created by wind into electric energy. According to the installation place, the wind power generating system is classified into an onshore system or an offshore system.
Typically, such a wind power generating system includes a tower which is supported on supporting ground, a nacelle which is provided on the upper end of the tower, and a blade which is coupled to the front end of the nacelle. The nacelle has therein several devices, such as a gear box, a generator, an inverter, etc., which are necessary to generate electricity. In the wind power generating system, the blade and the gear box convert kinetic energy created by wind into high-speed kinetic energy of 1500 rpm or more. The generator coupled to the gear box converts the high-speed kinetic energy into electric energy. Electricity produced by the generator is rectified by the inverter.
Here, in the case of electronic elements installed in the nacelle, the performance thereof may be lowered after they have been used for a predetermined period of time. Some of the elements may require replacement. Particularly, in the case where the wind power generating system is used offshore, abrupt malfunction may be induced by water, salinity, etc., so that an emergency repair may be required.
As such, when maintenance or repair of the nacelle is required, for example, to replace a malfunctioned element with a new one, a separate large crane may be used, or, alternatively, the entire upper surface of the nacelle may be opened to install a crane. Meanwhile, in the case where maintenance or repair of the tower or nacelle using a mechanical structure is required, a separate mechanism is necessary and sufficient space must be ensured.
Furthermore, in the case where elements in the nacelle malfunction, repair work must be rapidly and conveniently conducted. However, in the conventional technique, a separate large crane is required, or installation of a separate crane in the nacelle is necessary. Therefore, there are disadvantages in that efficiency of repair work is low, and a sufficiently large space must be ensured on or around the tower. Moreover, in the conventional technique, the entire upper surface of the nacelle must be opened for maintenance, in other words, a nacelle roof must be opened, thus making the repair work inconvenient and complex.